Climate Change in Bison Teeth

The fossil teeth of ancient bison can be used as a tool to reconstruct historic climate and vegetation changes in the Great Plains.

Bison roamed North America from Alaska to Mexico going back 200,000 years. They were the most abundant herbivores following the last ice age until Europeans began to settle the continent.

Their teeth hold evidence of the type of vegetation that grew in a particular location at a particular time, and that in turn provides information about climate fluctuations occurring on the plains, said Kathryn Hoppe, a UW acting assistant professor of Earth and space sciences.

The researchers used bison teeth collected in Montana, Wyoming, North and South Dakota, Nebraska, Kansas and Oklahoma. They broke up the enamel from tooth surfaces and dissolved samples in acid to release small amounts of carbon dioxide.

Then they used a mass spectrometer to examine the ratio of the isotopes carbon-12 to carbon-13. Different grasses, those that grow in warm and cool seasons for example, have different isotope ratios.

The results provided a means to reconstruct temperature patterns for particular locations at particular times, Hoppe said. Tooth enamel also carries evidence of changes in carbon dioxide levels, which helps scientists to see how levels of that greenhouse gas changed over time.

--LiveScience Staff

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Credit: Kathryn Hoppe